I learn SQL from this: http://www.w3schools.com/sql/sql_select.asp
SELECT LastName,FirstName FROM Persons
this show me:
LastName | FirstName
Hanse | Ola
Svendson | Tove
Pettersen | Kari
how can i add for this own columns without get data from DATABASE? for example:
SELECT TEST(default: aaa), LastName,FirstName FROM Persons
this should show me:
TEST | LastName | FirstName
aaa | Hanse | Ola
aaa | Svendson | Tove
aaa | Pettersen | Kari
SELECT 'aaa' as test, LastName,FirstName FROM Persons
If you want to create a "default" value on an actual field in a table you could use either the Coalesce or IsNull functions (please assume that Test is an actual field):
SELECT COALESCE(test, 'aaa') as Test, LastName,FirstName FROM Persons
SELECT ISNULL(test, 'aaa') as Test, LastName,FirstName FROM Persons
Both of these will return either the actual value of the field Test or 'aaa' if Test is Null.
We use COALESCE when retrieving the next Primary Key from a table (we don't use the Identity Property to maintain our PK's)
SELECT (COALESCE(MAX(PK), 0) + 1) FROM TableName
This way if there if the table doesn't contain any rows then 1 will be returned.
Randy has given best approach for an imagery field but if test is an actual field you can do this too..
select case when test is null then 'aaa' else test end, LastName,FirstName
FROM Persons;
will return aaa if test is null else test's value.
